Kinetic study of internalization and degradation of sup 131 I-labeled follicle-stimulating hormone in mouse Sertoli cells and its relevance to other systems

Journal Article · Tue Aug 15 04:00:00 EDT 1989 · Journal of Biological Chemistry; (USA)

OSTI ID:5478747

Shimizu, A; Kawashima, S ^[1]

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1. Hayashibara Biochemical Lab., Okayama (Japan)

The behavior of 131I-labeled follicle-stimulating hormone (FSH) after binding to cell-surface receptors in cultured Sertoli cells of C57BL/6NCrj mice was investigated. Sertoli cells cultured in F12/DME were pulse-labeled with 131I-FSH for 10 min at 4 degrees C, followed by cold chase for various periods of time. After the cold chase Sertoli cells were treated with 0.2 M acetate (pH 2.5) to dissociate membrane-bound 131I-FSH (surface radioactivity). The medium containing radioactivity after cold chase was mixed with 20% trichloroacetic acid, centrifuged, and the radioactivity of the supernatant was measured (degraded hormone). The radiolabeled materials associated with each process (surface binding, internalization, and degradation) were concentrated with ultrafiltration and characterized with gel filtration and/or thin layer chromatography. The effects of lysosomotropic agents, NH4Cl and chloroquine, were studied. The cold chase study at 32 degrees C showed that the surface radioactivity was the largest among the three kinds of radioactivities associated with each process immediately after pulse labeling, but the surface radioactivity rapidly decreased, while the internalized radioactivity increased. The cold chase study at 4 degrees C did not show such time-related changes in radioactivities, and a high level of surface radioactivity constantly persisted. The surface and internalized radioactivities were due to 131I-FSH, and the degraded radioactivity was mainly due to (131I)monoiodotyrosine. When Sertoli cells were cultured with lysosomotropic agents, the internalized radioactivity increased, while the degraded radioactivity decreased. Based on these observations, a kinetic model was proposed and the relationships among the surface, internalized, and degraded radioactivities and cold chase time were calculated algebraically.

• OSTI ID: 5478747
• Journal Information: Journal of Biological Chemistry; (USA), Journal Name: Journal of Biological Chemistry; (USA) Vol. 264:23; ISSN 0021-9258; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMMONIUM CHLORIDES
AMMONIUM COMPOUNDS
AMMONIUM HALIDES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CELL CONSTITUENTS
CELL CULTURES
CELL MEMBRANES
CHLORIDES
CHLORINE COMPOUNDS
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
FSH
GONADOTROPINS
HALIDES
HALOGEN COMPOUNDS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 131
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPE DILUTION
ISOTOPES
KINETICS
LYSOSOMES
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
METABOLISM
MICE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
PEPTIDE HORMONES
PITUITARY HORMONES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
RODENTS
SEPARATION PROCESSES
THIN-LAYER CHROMATOGRAPHY
TRACER TECHNIQUES
VERTEBRATES